Maximum Patio Slope and Still Feel Flat

aloha2009May 7, 2012

I know the standard is to have 1/4" drop per foot but have you ever been on a patio with a steeper grade and it still get relatively flat. One contractor said 1 1/4- 1 1/2 inch we wouldn't notice but I find that really hard to believe....and gave me question as to his integrity. The patio will be 18' so each little bit helps to minimize the frontage of the patio. Bottom line though the patio needs to "feel" flat.

Min. is 1/8" per ft. if the surface is smooth like concrete. Max. is 5/8", but stay less if you can. (This translates from between 1% to 5% slope.) 1 1/4" or 1 1/2" would be ridiculous and you'd definitely feel (and see!) it.

Thanks for giving me that range.
We thought 1 1/4" sounded ridiculous too---and this was someone that was recommended. The trouble is, besides this MAJOR bad suggestion, he's the 1st one that seemed to have good suggestions and otherwise cared about code.

Have you been on a patio with as steep as 5/8"? Most everything will be looking out into the yard except for the main table. Would it be uncomfortable at 5/8" for eating/drinking? I guess I can go around to some of the sidewalks in the neighborhood with our 6' level and check on the slope.

Whenever I'm faced with wondering how something might really seem, I make a physical mock up of it so I can see it. It would be sufficient for me to set a 2" x 4" level and drop one end by 5/8". Or do this with 2 of them on edge and place a flat board on top... or you might need to do this with a piece of stiff plywood or whatever else similar you can find laying around. Maybe a section of 2" x 12" will work. Just mock up something that allows you to evaluate it.

If you really prefer a flat patio/terrace, you could avoid using concrete which really does need to be pitched at 1.5% minimum for best minimum drainage. If you used a paving material that is more previous such as brick on sand or flagstone over sand/baserock or previous concrete paving, you could get away with 1% minimum slope as long as the surroundings don't add to the need for drainage.

Where large areas of concrete paving need to appear closer to level, the area to be paved usually incorporates a series of area drains centered within the patio with spacing determined by the maximum gradient you prefer. If it doesn't have to be solid concrete, a choice of some more previous modular pager allows for flatter layout.

Melvalena. Being that he seemed right on about everything else, we must have misunderstood each other. When he comes back with the bid, I will check (and recheck) if we end up going with him. The bid must be quite complex with the grading, steps, walkways and patios because they all seem to take a LONG time to get back.

It does worry me though, that only 1 contractor (this one) has showed how they knew how to handle incorporating the deck post - at least we think he's right. Most wanted to wrap the deck posts with plastic or cement spacer padding encased in cement. This one indicated that wasn't up to snuff and the deck post must be atop the footings otherwise the posts are more apt to rot. That's really sad that all these other contractors may indeed be creating HUGE problems for us down the line. I've tried to call about the city code but so far haven't gotten to a real live human being.

I used to landscape full time and one "professional" told my boss that it should be one inch in six feet but in reality such drops are way to steep (this is for laid pavers. Cement and asphalt are different)so we did one-half inch in six feet or less depending on area to be done.
People were very concerned with things rolling off of patio or tables.

The last job I did by myself I used one-quarter bubble on a three foot level as my prefered standard.
As this was on a very uneven surface, at one spot it had to got up to meet a steep several inches above all else, and she did not want any retaining wall type set-up. The longest run away from the house was apprx ten or eleven feet and on the other side of the steps I had to match to an existing side-walk.
I set stakes out where the patio would end to suit the topography.
I used a long STRAIGHT two by four to determine how much bubble I must use while setting the stakes for the base level.

It worked very well as where it had to be as close to appearing "level" as drop would allow it was and where it had to roll it all rolls just as needed to blend in.

A transit or new digital tool is fine for large areas but for smaller ones a two by four and level is all that is really needed.

Water will flow over a smooth surface like a drain pipe if the slope is 1% that is a 1 foot drop over 100 feet. this must be a continuous slope with no restriction at the destination or dips in the surface. (you can't achieve this with the quarter bubble method)It does sound like there is some confusion because if you say 1 1/4 or 1 1/2 FEET and not inches over the full 18 feet you are not far off this. Puddling is more of an issue because water will only flow if it is flat across the full surface.

Since the objective is "to minimize the frontage of the patio" is there some other way to achieve this without compromising your patio?

here's what hubby volunteered when I asked him to look at this thread again:

Deck posts? Does he mean the columns holding up the overhead cover?
I'm not trying to be picky or a know it all but Deck posts to me are what holds a wood deck off the ground below - I just want to be sure I'm addressing the right thing.

Its not uncommon in residential construction to set patio roof support posts right onto the concrete patio - the last house we had was done like this (redwood columns) and they lasted about 15 years. The bottoms started to show
signs of deterioration but the patio cover didn't sag.

Its also a somewhat common practice to wrap the column in roofing felt and put it down into the concrete - I've seen that done in commercial applications also. If there is any movement in the column (wind moving the overhead structure) I would think this method could allow the column to crack the concrete.

Home Depot and Lowes sell metal column bases that hold the column slightly off the ground. There are different types but they all perform the same function. Their purpose is to prevent the rotting of the bottom of the column.

Personally I'm not a fan of the appearance of the column bases so if I were to use them I'd want to investigate a "dressing up" of the lower portion of the column.

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Ok.. the above is how things are down here where we live, and what he's seen done on projects in various other parts of the country. Where you live, it might be necessary to do things differently.

Driveguy is right on. If you use an engineer scale tape, for 18' you'll drop .18 feet at 1%. That translates into 2-1/8" in 18'. I'm sure the contractor was talking about the total length. Most sidewalks fall at 2% I would stick with the 1% it will fall and if done right there should be minimal puddling.